A wireless device having multiple-input-multiple-output (MIMO) capability may receive signals from remote devices in a directional manner using an array of antennas coupled to corresponding RF chains. An advantage of receiving signals in a directional manner is that higher gains or receiver sensitivity may be achieved as compared to receiving signals in an omnidirectional manner. A further advantage is that signals from unwanted wireless devices (“non-target devices”) that are not situated within the target direction of the antenna array/RF chains are substantially attenuated to reduce signal interference from such devices.
A drawback associated with operating an antenna array/RF chains in a directional manner is that doing so consumes a relatively large amount of power. This is because many RF chains (e.g., 32) need to be operated in order to achieve the directional selectivity desired.
Often, a wireless device, which has its antenna array/RF chains configured in directional manner aimed at a target device, is waiting to receive another transmission from the target device. During such waiting period, the wireless device is consuming significant amount of power because its many RF chains are being operated to configure the antenna array in such directional manner.
Thus, there is a need to reduce power consumption while attempting to detect a signal from a target wireless device.